Solid dispersion forms of rifaximin

ABSTRACT

Provided herein are solid dispersions comprising rifaximin and pharmaceutical compositions and uses thereof.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/402,119, filed Sep. 30, 2016, the entire contents of which areincorporated herein by reference.

BACKGROUND

The incidence of liver disease is on the rise and will continue to be amajor health burden. Cirrhosis is a major cause of much of the chronicliver disease (CLD) in at least the U.S., and is the 12th leading causeof death. Mortality rates from complications of cirrhosis using datafrom the Nationwide Inpatient Sample (NIS) database from 1998 to 2006were estimated to be approximately 8%, 18%, 10%, and 45% for ascites,hepatic encephalopathy (HE), variceal bleeding, and hepatorenal syndrome(HRS), respectively. See e.g., Mol Pharm. 2011; 8:1573-1581. Similarly,other studies have demonstrated that the in-hospital mortality ofpatients with spontaneous bacterial peritonitis (SBP) ranges from10-50%. See e.g., Hepatology, 1993 February; 17(2):251-7; J Hepatol,2004 May; 40(5):823-30.

The management of cirrhosis and its complications is based on diseaseseverity and whether or not complications have developed (i.e.,decompensated disease). The development of esophageal variceal bleeding(EVB), ascites, spontaneous bacterial peritonitis (SBP), HE orhepatorenal syndrome (HRS) has a profound impact on prognosis. Despitecurrent medical therapies for EVB, ascites, SBP, and HE, patients withcompensated disease who develop one of these complications have afive-year survival rate of 20% to 50% (Gastroenterology 1987; 93:234-241; Gastroenterology. 1997; 112:463-472). The survival rate ofpatients who develop SBP or HRS is particularly poor. For SBP, less thanhalf will survive 1-year; the median survival rate for patients withtype I HRS is less than 2 weeks (Gastroenterology. 1993; 104:1133-8:Gastroenterology 1993; 105: 229-236).

The use of rifaximin in preventing complications of cirrhosis issupported by multiple lines of clinical and experimental evidence. Forexample, rifaximin was approved by the US FDA in March 2010 for thereduction in risk of recurrent overt HE; is shown to protect from HErecurrences with decreased HE-related and all-cause hospitalizationswithout an increased rate of adverse events (AEs) or decreased survival(see e.g., Conf. Proc. IEEE Eng. Med. Biol. Soc. 2013 2184-2187);reduces or maintains the overall rates of infection, antibiotic use, andother complications of cirrhosis such as ascites (see Conf. Proc. IEEEEng. Med. Biol. Soc. supra); and was independently associated withhigher survival and lower risk of developing variceal bleeding, HE, SBP,or HRS (see e.g., Journal of Gastroenterology and Hepatology 28(3);December 2012).

Given the therapeutic value of rifaximin, and the continued escalationof liver disease, alternative formulations, the discovery of alternativeformulations and uses of rifaximin remains.

SUMMARY

It has now been discovered that certain pharmaceutical compositionscomprising solid dispersions of rifaximin effectively reduce the time tohospitalization and prevent all-cause mortality associated withcomplications of liver disease. See e.g., FIG. 3 and FIG. 4.

It has also been discovered that certain pharmaceutical compositionscomprising solid dispersions of rifaximin reduce the time to developmentof refractory ascites. See e.g., Table 43.

The present disclosure provides these pharmaceutical compositions aswell as methods for their manufacture, and therapeutic uses associatedwith complications of liver disease.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 presents a Kaplan-Meier estimate for the distribution of time tohospitalization for any of the liver cirrhosis complications bytreatment group for an ITT (intent-to-treat) population with aformulation comprising rifaximin solid dispersion.

FIG. 2 presents a Kaplan-Meier estimate for the distribution of time toall-cause mortality by treatment group for an ITT population with aformulation comprising rifaximin solid dispersion.

FIG. 3 presents a Kaplan-Meier estimate for the distribution of time tohospitalization for any of the liver cirrhosis complications orall-cause mortality by treatment group for the ITT population with aformulation comprising rifaximin solid dispersion.

FIG. 4 presents a Kaplan-Meier estimate for the distribution of time tohospitalization for any of the liver cirrhosis complications orall-cause mortality by treatment group for the PP (per protocol)population with a formulation comprising rifaximin solid dispersion.

DETAILED DESCRIPTION

Provided herein are solid dispersions comprising rifaximin andhydroxypropyl methylcellulose acetate succinate (HPMC-AS).

Definitions

The term “solid dispersion” or as used herein refers to a dispersion ofrifaximin and an inert carrier matrix in a solid form, i.e., rifaximinis homologously mixed with an inert carrier. The inert matrix isgenerally hydrophilic (e.g., a polymer such as HPMC-AS) and may becrystalline or amorphous. It will be understood that it is notnecessarily the preparation method that governs the properties of thesolid dispersion, but rather the molecular arrangement of the contentsof the dispersion. Thus, absent an expression to do so, or anincorporation of process restrictions, solid dispersions are not to belimited by the process to which they are made. The terms “soliddispersion”, “soluble solid dispersion”, and the abbreviations “SD” or“SDD” are used interchangeably and each refer to the disclosed soliddispersion of rifaximin.

As used herein the terms “subject” and “patient” may be usedinterchangeably, and means a mammal in need of treatment, e.g.,companion animals (e.g., dogs, cats, and the like), farm animals (e.g.,cows, pigs, horses, sheep, goats and the like) and laboratory animals(e.g., rats, mice, guinea pigs and the like). Typically, the subject isa human in need of treatment.

The language “therapeutically effective amount” refers to an amount of acomposition comprising a solid dispersion of rifaximin effective, uponsingle or multiple dose administration to the subject to provide atherapeutic benefit to the subject.

“Hepatic encephalopathy” or “HE” for shorthand is defined as an alteredmental status diagnosed as HE and defined as an increase of the Connscore to Grade ≥2 (i.e., 0 or 1 to ≥2).

“Esophageal variceal bleeding” or “EVB” for shorthand is defined as theoccurrence of a clinically significant gastrointestinal bleed beingdefined as 1) bleeding from an esophageal or gastric varix at the timeof endoscopy or 2) the presence of large varices with blood evident inthe stomach, and no other identifiable cause of bleeding observed duringendoscopy, and at least one or more of the following criteria ispresent: i) drop in hemoglobin of greater than 2 g/dL over the first 48hours post hospital admission, ii) transfusion requirement of 2 units ofblood or more within 24 hours of hospital admission, iii) a systolicblood pressure of less than 100 mm Hg, or iv) pulse rate greater than100 beat/min at the time of admission.

“Spontaneous bacterial peritonitis or “SBP” for shorthand is defined asgreater than 250 polymorphonuclear (PMN) cells/mm³ and/or positivemonomicrobial culture in the ascitic fluid.

“Hepatorenal syndrome” (HRS) is defined as i) progressive rise in serumcreatinine (>1.5 mg/dL) with no improvement after at least 2 days withdiuretic withdrawal and volume expansion with albumin, ii) absence ofparenchymal kidney disease, iii) oliguria, iv) absence of shock, and v)no current or recent (within 3 months prior randomization) treatmentwith nephrotoxic drugs.

“Time to development of medically refractory ascites” is defined asascites which can either no longer be effectively managed by i) a lowsodium diet and maximal doses of diuretics (e.g., up to 400 mgspironolactone and 160 mg furosemide per day) or ii) diuretics, due tothe inability to tolerate side effects of maximal doses of diuretics.

In the present disclosure, when a numerical value is modified by theterm “about”, the exact numerical value is also deemed to be disclosed.

Compositions

In a first embodiment, the present disclosure provides a soliddispersion comprising rifaximin and HPMC-AS.

In a second embodiment, the present disclosure provides a soliddispersion comprising rifaximin and HPMC-AS, wherein the HPMC-AS ispresent in an amount of from about 10 wt % to about 60 wt %, from about10 wt % to about 50 wt %, from about 10 wt % to about 40 wt % from about12 wt % to about 38 wt %, from about 15 wt % to about 35 wt %, fromabout 16 wt % to about 34 wt %, from about 30 wt % to about 40 wt %,from about 30 wt % to about 35 wt %, from about 33 wt % to about 35 wt%, about 32 wt %, about 33 wt %, about 34 wt %, about 35 wt %, fromabout 10 wt % to about 20 wt %, from about 13 wt % to about 18 wt %,from about 16 wt % to about 18 wt %, about 15 wt %, about 16 wt %, about17 wt %, about 18 wt %, from about 40 wt % to about 50 wt %, from about46 wt % to about 49 wt %, about 46 wt %, about 47 wt %, or about 48 wt%. In one alternative, the amount of HPMC-AS present in the soliddispersion is about 46 wt % to about 49 wt %, about 46 wt %, about 47 wt%, about 48 wt %, from about 33 wt % to about 35 wt %, about 33 wt %,about 34 wt %, about 35 wt %, from about 16 wt % to about 34 wt %, fromabout 16 wt % to about 18 wt %, about 16 wt %, about 17 wt %, or about18 wt %. In another alternative, the amount of HPMC-AS present in thesolid dispersion is about 46 wt %, about 47 wt %, about 48 wt %, about33 wt %, about 34 wt %, about 35 wt %, about 16 wt %, about 17 wt %, orabout 18 wt % HPMC-AS. In yet another alternative, the amount of HPMC-ASpresent in the solid dispersion is about 46 wt %, about 47 wt %, orabout 48 wt %.

In a third embodiment, the solid dispersion comprises equal amounts ofrifaximin and polymer. Thus, for example, the solid dispersion comprisesfrom about 10 wt % to about 60 wt %, from about 10 wt % to about 50 wt%, from about 10 wt % to about 40 wt %, from about 12 wt % to about 38wt %, from about 15 wt % to about 35 wt %, from about 16 wt % to about34 wt %, from about 30 wt % to about 40 wt %, from about 30 wt % toabout 35 wt %, from about 33 wt % to about 35 wt %, about 32 wt %, about33 wt %, about 34 wt %, about 35 wt %, from about 10 wt % to about 20 wt%, from about 13 wt % to about 18 wt %, from about 16 wt % to about 18wt %, about 15 wt %, about 16 wt %, about 17 wt %, about 18 wt %, fromabout 40 wt % to about 50 wt %, from about 46 wt % to about 49 wt %,about 46 wt %, about 47 wt %, or about 48 wt % rifaximin and HPMC-AS. Inanother aspect, the solid dispersion comprises from about 46 wt % toabout 49 wt %, about 46 wt %, about 47 wt %, about 48 wt %, from about33 wt % to about 35 wt %, about 33 wt %, about 34 wt %, about 35 wt %,from about 16 wt % to about 34 wt %, from about 16 wt % to about 18 wt%, about 16 wt %, about 17 wt %, or about 18 wt % rifaximin and HMPC-AS.In another aspect, the solid dispersion comprises about 46 wt %, about47 wt %, about 48 wt %, about 33 wt %, about 34 wt %, about 35 wt %,about 16 wt %, about 17 wt %, or about 18 wt % rifaximin and HPMC-AS. Inyet another aspect, the solid dispersion comprises about 46 wt %, about47 wt %, or about 48 wt % rifaximin and HPMC-AS.

In a fourth embodiment, the solid dispersion comprising rifaximin andHPMC-AS further comprises poloxamer 407 (e.g., Pluronic® F-127), whereinthe remaining components and amounts present in the solid dispersion areas described in the second or third embodiment.

In a fifth embodiment, the solid dispersion comprising rifaximin andHPMC-AS further comprises poloxamer 407 (e.g., Pluronic® F-127) in anamount from about 0.5 wt % to about 7 wt %, from about 0.5 wt % to about5 wt %, from about 1 wt % to about 5 wt %, from about 1 wt % to about 4wt %, from about 2 wt % to about 4 wt %, from about 4 wt % to about 6 wt%, from about 3 wt % to about 5 wt %, from about 2 wt % to about 4 wt %,from about 1 wt % to about 2 wt %, about 1 wt %, about 2 wt %, about 3wt %, about 4 wt %, about 5 wt %, about 5.5 wt %, or about 6 wt %,wherein the remaining components and amounts present in the soliddispersion are as described in the second, third, or fourth embodiment.In one alternative, the solid dispersion comprises about 1 wt %, about 2wt %, about 3 wt %, about 4 wt %, about 5 wt %, about 5.5 wt %, about5.6 wt %, about 5.7 wt %, or about 6 wt % poloxamer 407 (e.g., Pluronic®F-127), wherein the remaining components and amounts present in thesolid dispersion are as described in the second, third, or fourthembodiment. In yet another alternative, the solid dispersion ofrifaximin comprises about 5 wt %, about 5.5 wt %, or about 6 wt %poloxamer 407 (e.g., Pluronic® F-127), wherein the remaining componentsand amounts present in the solid dispersion are as described in thesecond, third, or fourth embodiment.

In a sixth embodiment, provided are pharmaceutical compositionscomprising the solid dispersion of any one of the first, second, third,fourth, or fifth embodiment.

In a seventh embodiment, provided are pharmaceutical compositionscomprising the solid dispersions of any one of the first, second, third,fourth, or fifth embodiments together with croscarmellose sodium(crosslinked carboxymethyl cellulose sodium).

In an eighth embodiment, provided are pharmaceutical compositionscomprising the solid dispersions of any one of the first, second, third,fourth, or fifth embodiments together with croscarmellose sodium in anamount from about 2 wt % to about 15 wt %, from about 3 wt % to about 14wt %, from about 4 wt % to about 14 wt %, from about 2 wt % to about 13wt %, from about 3 wt % to about 13 wt %, from about 4 wt % to about 13wt %, from about 11 wt % to about 14 wt %, from about 12 wt % to about14 wt %, from about 4 wt % to about 10 wt %, about 12 wt %, about 12.5wt %, about 13 wt %, about 13.5 wt %, from about 4 wt % to about 6 wt %,about 5 wt %, from about 8% to about 10 wt %, or about 9 wt % based onthe total amount (wt %) of components in the pharmaceutical composition,wherein the remaining components and amounts present in thepharmaceutical composition include and are as described in the second,third, fourth, fifth, sixth, or seventh embodiment. In one alternative,the croscarmellose sodium is present in an amount from about 4 wt % toabout 14 wt %, from about 12 wt % to about 14 wt %, about 13 wt %, fromabout 4 wt % to about 6 wt %, about 5 wt %, from about 8% to about 10 wt%, or about 9 wt % based on the total amount (wt %) of components in thepharmaceutical composition, wherein the remaining components and amountspresent in the pharmaceutical composition include and are as describedin the second, third, fourth, fifth, sixth, or seventh embodiment. Inanother alternative, the croscarmellose sodium is present in an amountfrom of rifaximin is about 13 wt %, about 5 wt %, or about 9 wt % basedon the total amount (wt %) of components in the pharmaceuticalcomposition, wherein the remaining components and amounts present in thepharmaceutical composition include and are as described in the second,third, fourth, fifth, sixth, or seventh embodiment.

In a ninth embodiment, the pharmaceutical compositions described hereinfurther comprise microcrystalline cellulose, wherein the remainingcomponents and amounts present in the pharmaceutical composition includeand are as described in the second, third, fourth, fifth, sixth,seventh, or eighth embodiment.

In a tenth embodiment, the pharmaceutical compositions described hereinfurther comprise microcrystalline cellulose present in an amount fromabout 5 wt % to about 60 wt %, from about 10 wt % to about 55 wt %, fromabout 5 wt % to about 15 wt %, from about 8 wt % to about 13 wt %, fromabout 10 wt % to about 12 wt %, from about 10 wt % to about 19 wt %,about 11 wt %, from about 15 wt % to about 25 wt %, from about 17 wt %to about 19 wt %, about 18 wt %, from about 40 wt % to about 60 wt %,from about 45 wt % to about 55 wt %, from about 49 wt % to about 55 wt%, from about 49 wt % to about 51 wt %, from about 53 wt % to about 55wt %, about 50 wt %, or about 54 wt % based on the total amount (wt %)of components in the pharmaceutical composition, wherein the remainingcomponents and amounts present in the pharmaceutical composition includeand are as described in the second, third, fourth, fifth, sixth,seventh, eighth, or ninth embodiment.

In an eleventh embodiment, the pharmaceutical compositions describedherein further comprise colloidal silicon dioxide, wherein the remainingcomponents and amounts present in the pharmaceutical composition includeand are as described in the second, third, fourth, fifth, sixth,seventh, eighth, ninth, or tenth embodiment.

In a twelfth embodiment, the pharmaceutical compositions describedherein further comprise colloidal silicon dioxide present in an amountfrom about 0.1 wt % to about 0.3 wt %, from about 0.15 wt % to about0.25 wt %, or about 0.2 wt % based on the total amount (wt %) ofcomponents in the pharmaceutical composition, wherein the remainingcomponents and amounts present in the pharmaceutical composition includeand are as described in the second, third, fourth, fifth, sixth,seventh, eighth, ninth, tenth, or eleventh embodiment.

In a thirteenth embodiment, the pharmaceutical compositions describedherein further comprise magnesium stearate, wherein the remainingcomponents and amounts present in the pharmaceutical composition includeand are as described in the second, third, fourth, fifth, sixth,seventh, eighth, ninth, tenth, eleventh, or twelfth embodiment.

In a fourteenth embodiment, the pharmaceutical compositions describedherein further comprise magnesium stearate present in an amount fromabout 0.3 wt % to about 0.6 wt %, from about 0.4 wt % to about 0.6 wt %,from about 0.45 wt % to about 0.55 wt %, about 0.45 wt %, about 0.47 wt%, or about 0.49 wt % based on the total amount (wt %) of components inthe pharmaceutical composition, wherein the remaining components andamounts present in the pharmaceutical composition include and are asdescribed in the second, third, fourth, fifth, sixth, seventh, eighth,ninth, tenth, eleventh, twelfth, or thirteenth embodiment.

In a fifteenth embodiment, provided is a provided is a pharmaceuticalcomposition comprising from about 33 wt % to about 35 wt % rifaximin;from about 33 wt % to about 35 wt % HPMC-AS; from about 3 wt % to about5 wt % poloxamer 407; from about 4 wt % to about 14 wt % croscarmellosesodium; from about 10 wt % to about 19 wt % microcrystalline cellulose;from about 0.15 wt % to about 0.25 wt % colloidal silicon dioxide; andfrom about 0.45 wt % to about 0.55 wt % magnesium stearate.

In a sixteenth embodiment, provided is a pharmaceutical compositionaccording to the fifteenth embodiment, wherein comprising thecroscarmellose sodium is present in an amount of from about 12 wt % toabout 14 wt %. Alternatively, provided is a pharmaceutical compositionaccording to the fifteenth embodiment, wherein comprising thecroscarmellose sodium is present in an amount of about 13%.

In a seventeenth embodiment, provided is a pharmaceutical compositionaccording to the fifteenth or sixteenth embodiment wherein themicrocrystalline cellulose is present in an amount from about 10 wt % toabout 12 wt %. Alternatively, provided is a pharmaceutical compositionaccording to the fifteenth or sixteenth embodiment wherein themicrocrystalline cellulose is present in an amount of about 11 wt %.

In an eighteenth embodiment, provided is a pharmaceutical compositionaccording to the fifteenth embodiment, wherein the croscarmellose sodiumis present in an amount from about 4 wt % to about 6 wt %.Alternatively, provided is a pharmaceutical composition according to thefifteenth embodiment, wherein the croscarmellose sodium is present in anamount of about 5 wt %.

In a nineteenth embodiment, provided is a pharmaceutical compositionaccording to the fifteenth or eighteenth embodiment, wherein themicrocrystalline cellulose is present in an amount from about 17 wt % toabout 19 wt %. Alternatively, provided is a pharmaceutical compositionaccording to the fifteenth or eighteenth embodiment, wherein themicrocrystalline cellulose is present in an amount of about 18 wt %.

In a twentieth embodiment, provided is a pharmaceutical compositionaccording to the fifteenth, sixteenth, seventeenth, eighteenth, ornineteenth embodiment, wherein the poloxamer 407 is present in an amountof about 4%.

In a twenty-first embodiment, provided is a pharmaceutical compositionaccording to the fifteenth, sixteenth, seventeenth, eighteenth,nineteenth, or twentieth embodiment, wherein the colloidal silicondioxide is present in an amount of about 0.20 wt %.

In a twenty-second embodiment, provided is a pharmaceutical compositionaccording to the fifteenth, sixteenth, seventeenth, eighteenth,nineteenth, twentieth, or twenty-first embodiment, wherein the magnesiumstearate is present in an amount of about 0.50 wt %.

In a twenty-third embodiment, provided is a pharmaceutical compositionaccording to the fifteenth, sixteenth, seventeenth, eighteenth,nineteenth, twentieth, twenty-first, or twenty-second embodiment,wherein the rifaximin is present in an amount of about 34%.

In a twenty-fourth embodiment, provided is a pharmaceutical compositionaccording to the fifteenth, sixteenth, seventeenth, eighteenth,nineteenth, twentieth, twenty-first, twenty-second, or twenty-thirdembodiment, wherein the HPMC-AS is present in an amount of about 34%.

In a twenty-fifth embodiment, provided is a pharmaceutical compositionaccording to the fifteenth, sixteenth, seventeenth, eighteenth,nineteenth, twentieth, twenty-first, twenty-second, twenty-thirdembodiment, or twenty fourth embodiment, wherein the total amount ofrifaximin is about 80 mg.

In a twenty-sixth embodiment, provided is a pharmaceutical compositioncomprising from about 16 wt % to about 18 wt % rifaximin; from about 16wt % to about 18 wt % HPMC-AS; from about 1 wt % to about 2 wt %poloxamer 407; from about 4 wt % to about 10 wt % croscarmellose sodium;from about 49 wt % to about 55 wt % microcrystalline cellulose; fromabout 0.15 wt % to about 0.25 wt % colloidal silicon dioxide; and fromabout 0.45 wt % to about 0.55 wt % magnesium stearate.

In a twenty-seventh embodiment, provided is a pharmaceutical compositionaccording to the twenty-sixth embodiment, wherein the croscarmellosesodium is present in an amount from about 8 wt % to about 10 wt %.Alternatively, provided is a pharmaceutical composition according to thetwenty-sixth embodiment, wherein the croscarmellose sodium is present inan amount of about 9 wt %.

In a twenty-eighth embodiment, provided is a pharmaceutical compositionaccording to the twenty-sixth or twenty-seventh embodiment, wherein themicrocrystalline cellulose is present in an amount from about 49 wt % toabout 51 wt %. Alternatively, provided is a pharmaceutical compositionaccording to the twenty-sixth or twenty-seventh embodiment, wherein themicrocrystalline cellulose is present in an amount of about 51 wt %.

In a twenty-ninth embodiment, provided is a pharmaceutical compositionaccording to the twenty-sixth embodiment, wherein the croscarmellosesodium is present in an amount from about 4 wt % to about 6 wt %.Alternatively, provided is a pharmaceutical composition according to thetwenty-sixth embodiment, wherein the croscarmellose sodium is present inan amount of about 5 wt %.

In a thirtieth embodiment, provided is a pharmaceutical compositionaccording to the twenty-sixth or twenty-ninth embodiment, wherein themicrocrystalline cellulose is present in an amount from about 53 wt % toabout 55 wt %. Alternatively, provided is a pharmaceutical compositionaccording to the twenty-sixth or twenty-ninth embodiment, wherein themicrocrystalline cellulose is present in an amount of about 54 wt %.

In a thirty-first embodiment, provided is a pharmaceutical compositionaccording to the twenty-sixth, twenty-seventh, twenty-eighth,twenty-ninth, or thirtieth embodiment, wherein colloidal silicon dioxideis present in an amount of about 0.20 wt %.

In a thirty-second embodiment, provided is a pharmaceutical compositionaccording to the twenty-sixth, twenty-seventh, twenty-eighth,twenty-ninth, thirtieth, or thirty-first embodiment, wherein themagnesium stearate is present in an amount of about 0.50 wt %.

In a thirty-third embodiment, provided is a pharmaceutical compositionaccording to the twenty-sixth, twenty-seventh, twenty-eighth,twenty-ninth, thirtieth, thirty-first, or thirty-second embodiment,wherein the rifaximin is present in an amount of about 17 wt %.

In a thirty-fourth embodiment, provided is a pharmaceutical compositionaccording to the twenty-sixth, twenty-seventh, twenty-eighth,twenty-ninth, thirtieth, thirty-first, thirty-second, or thirty-thirdembodiment, wherein the HMPC-AS is present in an amount of about 17 wt%.

In a thirty-fifth embodiment, provided is a pharmaceutical compositionaccording to the twenty-sixth, twenty-seventh, twenty-eighth,twenty-ninth, thirtieth, thirty-first, thirty-second, thirty-third, orthirty-fourth embodiment, wherein the total amount of rifaximin is 40mg.

In a thirty-sixth embodiment, the pharmaceutical compositions describedherein are in the form of a tablet.

In a thirty-seventh embodiment, the pharmaceutical compositionsdescribed herein are in the form of a tablet, and are immediate releaseor sustained extended release. In one alternative, the pharmaceuticalcomposition is a sustained extended release tablet.

In a thirty-eighth embodiment, the pharmaceutical compositions describedherein are film coated. Coatings are known to those of skill in the artand may immediate release or sustained release coatings. An example of afilm coating is Opadry II Blue 85F90614 by Colorcon®.

Other solid dispersions and pharmaceutical compositions included in thepresent disclosure are described in the Exemplification section below.

Uses, Formulation and Administration Dosage Forms

According to other embodiments, the present disclosure relates to amethod of using the disclosed solid dispersions pharmaceuticalcompositions thereof to prevent complications of liver cirrhosis such ase.g., in subjects with early decompensation.

Also provided herein are methods of using the solid dispersions andpharmaceutical compositions thereof to prevent all-cause mortality e.g.,in subjects with liver cirrhosis who may also have early decompensation.

Also provided herein are methods of using the solid dispersions andpharmaceutical compositions thereof to reduce the time tohospitalization that is associated with complications of liver disease(e.g., liver cirrhosis complications) such as e.g., reducing the time tohospitalization from one or more of hepatic encephalopathy (HE),esophageal variceal bleeding (EVB), spontaneous bacterial peritonitis(SBP), and hepatorenal syndrome (HRS).

Also provided herein are methods of using the solid dispersions andpharmaceutical compositions thereof to prevent hospitalization that isassociated with complications of liver disease (e.g., liver cirrhosiscomplications) such as e.g., reducing the time to hospitalization fromone or more of hepatic encephalopathy (HE), esophageal variceal bleeding(EVB), spontaneous bacterial peritonitis (SBP), and hepatorenal syndrome(HRS).

Also provided herein are methods of using the solid dispersions andpharmaceutical compositions thereof to reduce the time to all-causemortality that is associated with complications of liver disease (e.g.,liver cirrhosis complications) such as e.g., reducing the time toall-cause mortality from one or more of hepatic encephalopathy (HE),esophageal variceal bleeding (EVB), spontaneous bacterial peritonitis(SBP), and hepatorenal syndrome (HRS).

Also provided herein are methods of using the solid dispersions andpharmaceutical compositions thereof to prevent all-cause mortality thatis associated with complications of liver disease (e.g., liver cirrhosiscomplications) such as e.g., reducing the time to all-cause mortalityfrom one or more of hepatic encephalopathy (HE), esophageal varicealbleeding (EVB), spontaneous bacterial peritonitis (SBP), and hepatorenalsyndrome (HRS).

Further provided are methods of using the solid dispersions andpharmaceutical compositions thereof to reduce the time to development ofrefractory ascites in e.g., subjects having early decompensated livercirrhosis or liver cirrhosis complications such as HE, EVB, SBP, or HRS.

Suitable dosage forms that can be used with the solid dispersions andcompositions herein include, but are not limited to, capsules, tablets,mini-tablets, beads, beadlets, pellets, granules, granulates, andpowder. Suitable dosage forms may be coated, for example using anenteric coating. In some embodiments, the solid dispersions andcompositions are formulated as tablets, caplets, or capsules. In oneembodiment, the solid dispersions and compositions are formulated as atablet.

Provided compositions may be formulated such that a dosage of between0.001-100 mg/kg body weight/day of the inhibitor can be administered toa patient receiving these compositions. It should also be understoodthat a specific dosage and treatment regimen for any particular patientwill depend upon a variety of factors, including age, body weight,general health, sex, diet, time of administration, rate of excretion,drug combination, the judgment of the treating physician, and theseverity of the particular disease being treated. The amount of aprovided dispersion in the composition will also depend upon theparticular compound in the composition. In one aspect, the dosage amountof rifaximin in a provided composition is 40 mg. In another aspect, thedosage amount of rifaximin in a provided composition is 80 mg.

EXEMPLIFICATION General Preparation of Solid Dispersions

The solid dispersions described herein can be prepared by a number ofmethods, including by melting and solvent evaporation. The soliddispersions of the present invention can also be prepared according tothe procedures described in: Chiou W L, Riegelman S: “Pharmaceuticalapplications of solid dispersion systems”, J. Pharm. Sci. 1971; 60:1281-1302; Serajuddin ATM: “Solid dispersion of poorly water-solubledrugs: early promises, subsequent problems, and recent breakthroughs”,J. Pharm. Sci. 1999; 88: 1058-1066; Leuner C, Dressman J: “Improvingdrug solubility for oral delivery using solid dispersions”, Eur. J.Pharm. Biopharm. 2000; 50:47-60; and Vasconcelos T, Sarmento B, Costa P:“Solid dispersions as strategy to improve oral bioavailability of poorwater soluble drugs”, Drug Discovery Today 2007; 12:1068-1075, all ofwhich are incorporated herein by reference in their entireties.

In one aspect, the components, e.g., rifaximin, polymer and methanol aremixed and then spray dried. Exemplary conditions are summarized in Table1 below.

Exemplary Spray Drying Process Parameters, include for example:

-   -   Spray Dryer—e.g., PSD 1;    -   Single or multi-fluid nozzle: e.g., a two Fluid Niro Nozzle;    -   Nozzle orifice—0.1-10 mm;    -   Inlet gas temperature—75-150±5 deg C.;    -   Process gas flow (mmH2O)—20-70, preferred 44;    -   Atomizing gas pressure—0.7-1 bar;    -   Feed rate—2-7 kg/Hr;    -   Outlet temperature—30-70±3 deg C.;    -   Solution temperature—20-50 deg C.; and        Post spray drying vacuum dry at 20-60 deg C., for between about        2 and 72 hrs.

TABLE 1 Inlet Outlet temp. Aspi- Inlet temp. temp. Spray Description(set, rator Pump (measured, (measured, rate (b) (a) ° C.) % % ° C.) °C.) mL/min (50:50) 120 95 40-30 120-119 60-45 9.6 HPMC- AS:rifaximin,~10 g scale (a): approximate ratio of rifaximin to HPMC-AS, by weight.(b): flow rates are estimated at 30% pump.

A representative batch formula is provided in Table 2.

TABLE 2 Theoretical % Quantity Ingredient Function w/w (kg/batch)Rifaximin Active 47.20 22.18 HPMC-AS Polymer 47.20 22.18 Poloxamer 407Surfactant 5.60 2.64 Methanol^(a) Solvent — (438.0) Nitrogen^(b) Processgas — — Total Theoretical Weight 100.00 47.00 ^(a)Removed during dryingprocess; ^(p)rocess gas for drying and atomization; not incorporated inproduct

Blending/Encapsulation Procedure

The components and composition of an 80 mg and 40 mg immediate andsustained extended release tables are proved in Table 3 below.

TABLE 3 Theoretical Quantity (mg/tablet) Ingredient Function 80 mg-IR 80mg-SER 40 mg-IR 80 mg-IR Rifaximin Active 80 80 40 40 HPMC-AS Polymer 8080 40 40 Poloxamer 407 Surfactant 9.49 9.49 4.75 4.75 Croscarmellosesodium Dissolution enhancer 30.15 11.33 20.74 11.33 Microcrystallinecellulose Filler 25.28 44.10 119.43 128.84 Colloidal silicon dioxideGlidant 0.45 0.45 0.45 0.45 Magnesium stearate Lubricant 1.13 1.13 1.131.13 (non-bovine) Opadry II Blue 85F90614 Coating 11.92 11.92 11.9211.92 (PVA coating) Purified Water Solvent for — — — — Coating solutionTotal Theoretical Weight 238.42 238.42 238.42 238.42

Clinical Data

The following data was obtained using the compositions described inTable 3.

A Phase 2, randomized, double-blind, placebo-controlled, parallelmulticenter study evaluation of the efficacy (prevention ofhospitalization for complications of liver cirrhosis or all-causemortality in subjects with early decompensation) and safety of rifaximinSSD tablets in subjects with early decompensated liver cirrhosis wasconducted. Subjects with documented ascites who had not previouslyexperienced SBP, EVB, or HRS were enrolled in the study. Subjectscompleted a 1 to 21-day Screening Period, a 24-week Treatment Period,and a 2-week Follow-up Period. Approximately 420 subjects whosuccessfully completed the Screening Period were randomized in a1:1:1:1:1:1 allocation to 1 of 6 treatment groups and entered theTreatment Period. All treatments were administered once daily atbedtime. Assessments of efficacy and safety were performed during clinicvisits at Day 1 (baseline), Weeks 2, 4, 8, 12, 16, 20, and 24 (End ofTreatment [EOT]). All subjects completed an End of Study (EOS) visit atWeek 26 (or early termination if applicable) for final safetyassessments.

Inclusion Criteria

A subject was eligible for inclusion in this study if he/she met all ofthe following criteria:

1. Subject was ≥18 years of age.2. Subject was male or female.

Females of childbearing (reproductive) potential had to have a negativeserum pregnancy test at Screening and had to agree to use an acceptablemethod of contraception throughout their participation in the study.Acceptable methods of contraception included double barrier methods(condom with spermicidal jelly or a diaphragm with spermicide), hormonalmethods (eg, oral contraceptives, patches or medroxyprogesteroneacetate), or an intrauterine device (IUD) with a documented failure rateof less than 1% per year. Abstinence or partner(s) with a vasectomycould be considered an acceptable method of contraception at thediscretion of the investigator. Note: Females who had been surgicallysterilized (eg, hysterectomy or bilateral tubal ligation) or who werepostmenopausal (total cessation of menses for >1 year) were notconsidered “females of childbearing potential.”

3. Subject had a diagnosis of liver cirrhosis and documented ascites,either by imaging study or physical exam (Note: Subjects with Grade 1ascites were permitted in the study), but had not yet experienced any ofthe following complications of cirrhosis:

-   -   EVB—clinically significant gastrointestinal bleed    -   SBP—greater than 250 polymorphonuclear (PMN) cells/mm³ and/or        positive monomicrobial culture in the ascitic fluid    -   Renal failure in the presence of ascites—rise in the serum        creatinine by 0.5 mg/dL (to greater than 1.5 mg/dL), with        ascites documented on physical examination, imaging, and/or        admitted on diuretics for the treatment of ascites    -   Development of medically refractory ascites.        4. Subject had a MELD score of ≥12, a MELDNa score of ≥12, or a        Child-Pugh B Classification (score=7-9).        5. Subject was capable of understanding the requirements of the        study, and was willing to comply with all study procedures.        6. Subject understood the language of the informed consent form,        and was capable and willing to sign the informed consent form.        7. If applicable, subject had a close family member or other        personal contact that could provide continuing oversight to the        subject and was available to the subject during the conduct of        the trial.

Exclusion Criteria

A subject was not eligible for inclusion in this study if any of thefollowing criteria applied:

1. Subject had a history of a major psychiatric disorder, includinguncontrolled major depression or controlled or uncontrolled psychoseswithin the past 24 months prior to signing the informed consent(Diagnostic and Statistical Manual of Mental Disorders, 4th.) that, inthe opinion of the investigator, would prevent completion of the study,interfere with analysis of study results, or negatively impact thesubject's participation in the study.2. Subject had history of alcohol abuse or substance abuse within thepast 3 months prior to signing the informed consent (Diagnostic andStatistical Manual of Mental Disorders, 4th.).3. Subject had documented primary sclerosing cholangitis (Note: subjectswith primary biliary cirrhosis were allowed in the study).4. Subject had undergone prophylactic variceal banding within 2 weeks ofScreening or was scheduled to undergo prophylactic variceal bandingduring the study (Note: subjects with previous prophylactic varicealbanding were allowed to participate in the study).5. Subject had been diagnosed with an infection for which they arecurrently taking oral or parenteral antibiotics.6. Subject had significant hypovolemia, or any electrolyte abnormalitythat could affect mental function (eg, serum sodium <125 mEq/L, serumcalcium >10 mg/dL).7. Subject had severe hypokalemia as defined by a serum potassiumconcentration <2.5 mEq/L.8. Subject was anemic, as defined by a hemoglobin concentration of ≤8g/dL.9. Subject had renal insufficiency with a creatinine of ≥1.5 mg/dL.

-   -   Note: Laboratory tests related to Inclusion/Exclusion criteria        could be repeated once, before considering subject as a        Screening Failure (given all other Inclusion/Exclusion criteria        are met/not met respectively) at the discretion of the        Investigator.        10. Subject showed presence of intestinal obstruction or has        inflammatory bowel disease.        11. Subject had Type 1 or Type 2 diabetes that was poorly        controlled in the opinion of the investigator or had had an        HbA1c>12% within the past 3 months prior to Screening or at the        Screening visit.        12. Subject had a history of seizure disorders.        13. Subject had unstable cardiovascular or pulmonary disease,        categorized by a worsening in the disease condition that        required a change in treatment or medical care within 30 days of        randomization.        14. Subject had an active malignancy within the last 5 years        (exceptions: basal cell carcinomas of the skin, or if female, in        situ cervical carcinoma that had been surgically excised).        15. Subject had hepatocellular carcinoma (HCC). Note:        Alpha-fetoprotein (AFP) concentration was measured at Screening.        If the AFP was greater than 200 ng/mL, the subject was excluded        from participation in the study. If the AFP was above the upper        limit of normal and ≤200 ng/mL, cross-sectional imaging or        ultrasonography techniques had to be used to rule out HCC.        16. Subject had any condition or circumstance that adversely        affected the subject or could cause noncompliance with treatment        or visits, could affect the interpretation of clinical data, or        could otherwise contraindicate the subject's participation in        the study.        17. If female, subject was pregnant or at risk of pregnancy, or        was lactating.        18. Known varicella, herpes zoster, or other severe viral        infection within 6 weeks of randomization.        19. Known human immunodeficiency virus (HIV) infection.        20. Subject had a positive stool test for Yersinia        enterocolitica, Campylobacter jejuni, Salmonella, Shigella, ovum        and parasites, and/or Clostridium difficile.        NOTE: Results of stool tests had to be confirmed as negative        prior to randomization.        21. Subject had a history of tuberculosis infection and/or had        received treatment for a tuberculosis infection. If subject had        a previous positive skin test for tuberculosis antigen then they        were to have a current negative chest X-ray to be eligible and        could not have received previous treatment.        22. Subject was an employee of the site that was directly        involved in the management, administration, or support of this        study or was an immediate family member of the same.        23. Subject had a history of hypersensitivity to rifaximin,        rifampin, rifamycin antimicrobial agents, or any of the        components of rifaximin SSD.        24. Subject used any investigational product or device, or        participated in another research study within 30 days prior to        randomization.        25. Subject had a documented overt HE episode (Conn score ≥2)        that had not resolved within 30 days of Visit 1 (Screening).

Treatments Administered

There were 6 treatment groups as listed below. The compositionalcomponents are presented above in Table 3. All treatments were to beadministered orally qhs (at every bedtime). The duration of thetreatment was 24 weeks.

Treatment A: rifaximin SSD 40 mg qhs (IR (immediate release) tablet)

Treatment B: rifaximin SSD 80 mg qhs (IR tablet)

Treatment C: rifaximin SSD 40 mg qhs (SER (sustained extended release)tablet)

Treatment D: rifaximin SSD 80 mg qhs (SER tablet)

Treatment E: rifaximin SSD 80 mg qhs (IR tablet)+rifaximin 80 mg qhs(SER tablet)

Treatment F: Placebo qhs

Primary Efficacy Endpoints

Over the 24-week treatment period, the primary efficacy endpoint for thestudy was time to:

-   -   All-cause mortality, or    -   Hospitalization that was associated with 1 of the following        complications of liver disease:        -   HE—altered mental status diagnosed as HE, and defined as an            increase of the Conn score to Grade ≥2 (ie, 0 or 1 to ≥2).        -   EVB—occurrence of a clinically significant gastrointestinal            bleed was defined as:            -   Bleeding from an esophageal or gastric varix at the time                of endoscopy, or            -   The presence of large varices with blood evident in the                stomach, and no other identifiable cause of bleeding                observed during endoscopy.            -   In addition, 1 or more of the following criteria had to                be present:                -   Drop in hemoglobin of greater than 2 g/dL over the                    first 48 hours post hospital admission,                -   Transfusion requirement of 2 units of blood or more                    within 24 hours of hospital admission,                -   A systolic blood pressure of less than 100 mm Hg, or                -   Pulse rate greater than 100 beat/min at the time of                    admission.                    Note: Baveno IV criteria was also used to further                    define variceal bleeding episodes.    -   SBP—greater than 250 PMNcells/mm³ and/or positive monomicrobial        culture in the ascitic fluid.    -   HRS was defined as:        -   Progressive rise in serum creatinine (>1.5 mg/dL) with no            improvement after at least 2 days with diuretic withdrawal            and volume expansion with albumin;        -   Absence of parenchymal kidney disease;        -   Oliguria;        -   Absence of shock; and        -   No current or recent (within 3 months prior randomization)            treatment with nephrotoxic drugs.

Key Secondary Efficacy Endpoints

The key secondary efficacy endpoints of this study were overallhospitalization rate for each of the individual component of the primaryendpoint or all-cause mortality over the 24-week treatment period.

Other Secondary Endpoints

Other secondary endpoints of this study were the following:

-   -   Time to first hospitalization or all-cause mortality for each        individual component of the primary endpoint.    -   All-cause hospitalization rate over the 24-week Treatment        Period.    -   Liver cirrhosis mortality over the 24-week Treatment Period.    -   Time to development of medically refractory ascites, defined as        ascites which could either no longer be effectively managed by:    -   A low sodium diet and maximal doses of diuretics (up to 400 mg        spironolactone and 160 mg furosemide per day), or    -   Diuretics, due to the inability to tolerate side effects of        maximal doses of diuretics.    -   Hospitalizations over the 24-week treatment period for all other        infections.    -   Hospitalization as the result of Acute Kidney Injury (AKI) that        was not attributable to HRS and was defined by a rapid reduction        (over less than 48 hours) of kidney function as evidenced by:    -   A rise in serum creatinine, (with either an absolute increase in        serum creatinine of ≥0.3 mg/dL (≥26.4 μmol/L) or percentage        increase in serum creatinine of ≥50%), and    -   A reduction in urine output (defined as <0.5 ml/kg/hr for more        than 6 hours).    -   Change in indices of Health Outcomes (Chronic Liver Disease        Questionnaire (CLDQ_, Gastrointestinal Symptom Rating Scale        (GSRS), Caregiver Burden Inventory (CBI), Epworth Sleepiness        Scale (ESS)) at Weeks 4, 8, 12, 16, 20 and 24.    -   Pharmacokinetics of rifaximin and 25-desacetyl rifaximin        assessing effects on factors including hepatic impairment, renal        impairment and concomitant medications.    -   The critical flicker frequency (CFF) was assessed for each        subject. CFF was assessed using a specialized CFF instrument.    -   Changes from baseline in blood ammonia concentrations at Weeks        2, 4, 8, 12, 16, 20 and 24.    -   Change from baseline in MELD (Model for End-Stage Liver Disease)        and MELDNa (model end stage liver disease sodium) score at Weeks        2, 4, 8, 12, 16, 20 and 24.    -   Change from baseline in Child-Pugh score at Weeks 2, 4, 8, 12,        16, 20 and 24.

Drug Concentration Measurements

Rifaximin and metabolite concentration data was collected according tothe Full Population PK Sampling design recommended in the FDA Guidancefor Industry: Population Pharmacokinetics.

Disposition of Subjects

A total of 518 subjects were randomized in the study, of which 408(78.8%) completed the study:

-   -   64 subjects in the 40 mg qhs IR group,    -   63 subjects in the 80 mg qhs IR group,    -   68 subjects in the 40 mg qhs SER group,    -   68 subjects in the 40 mg qhs SER group, 7    -   2 subjects in the 80 mg qhs SER group,    -   66 subjects in the combined IR/SER group and    -   75 subjects in the placebo group.

In total, 109 (21.0%) subjects prematurely discontinued from the study,with the largest number of discontinuations observed in the 80 mg qhs IRgroup (30.4%). The most common reason of premature discontinuationreported in the study was “withdrawal by subject”; this accounted forthe premature discontinuation of 44 (8.5%) of all subjects that wererandomized. This was followed by “death” which accounted for thepremature discontinuation of 21 (4.1%) of all randomized subjects. Ofall treatment groups, the 80 mg qhs IR group experienced the most numberof premature discontinuations from the study (28 subjects in total),with “withdrawal by subject” reported as the most common reason ofpremature discontinuation (n=9).

Data Sets Analyzed

Two datasets were analyzed: ITT population and PP populations.

-   -   ITT population was defined as all randomized subjects who took        at least 1 dose of study drug.    -   PP population was defined as all subjects in the ITT population        with the exception of those who failed to meet inclusion        criteria 3 or 4, or meet exclusion criterion 1.    -   Safety population included all randomized subjects who took at        least 1 dose of study drug.

The analyses of baseline characteristics and efficacy were performed onthe ITT population. The primary efficacy analyses were also performed onthe PP population as a sensitivity analysis.

Analysis of Efficacy

The primary efficacy endpoint was the time to all-cause mortality orhospitalization that was associated with 1 of the followingcomplications of liver disease: HE, EVB, SBP, or HRS over the 24-weektreatment period was performed on the ITT population.

The primary analysis of time to hospitalization for any of the livercirrhosis complications or all-cause mortality specified for the primaryendpoint utilized a log-rank test stratified by analysis region (2-sidedtest at a significance level of 0.05).

Pairwise treatment group comparisons (each of the rifaximin SSD groupsversus placebo) utilizing the log-rank test was also performed.

Additionally, Kaplan-Meier methods were used to estimate the proportionof subjects experiencing hospitalization for any of the liver cirrhosiscomplications or all-cause mortality on Days 28, 56, 84, 112, 140, and168 for each treatment group.

Other analyses of the primary efficacy endpoint include sensitivityanalyses (primary efficacy endpoint analyses using PP population) andprespecified subgroup analyses.

Time to Hospitalization for any of the Liver Cirrhosis Complications orall-Cause Mortality

The primary efficacy endpoint was the time to all-cause mortality orhospitalization that was associated with 1 of the followingcomplications of liver disease: HE, EVB, SBP, or HRS over the 24-weektreatment period. Subjects who terminated early for reasons other thandeath were contacted approximately 24 weeks from randomization todetermine if they experienced the primary endpoint. In the case of asubject's death, the subject's caregiver (if applicable) was contacted.

The time to hospitalization for any of the liver cirrhosis complicationsor all-cause mortality was defined as the duration between the date offirst dose of the study drug and the date of first hospitalization forany of the liver cirrhosis complications or all-cause mortality.

Subjects who completed the entire 24-week treatment period without deathor meeting the definition of liver cirrhosis complications of HE, EVB,SBP, or HRS were censored at the date of final visit (date of lastcontact). Subjects who prematurely discontinued before the end of the24-week treatment period for reasons other than death were contactedmonthly via a follow-up phone call for capture of cirrhosiscomplications, hospitalization, or death information. Subjects who didnot meet the primary endpoint were censored at the date of last contact.

Primary Efficacy Analysis

The primary analysis did not demonstrate an overall statisticallysignificant difference in time to hospitalization for any of the livercirrhosis complications or all-cause mortality up to 24 weeks in anygroup. The overall treatment comparison effect for any of the rifaximinSSD treatments versus placebo was not statistically significant(stratified log-rank p=0.8062) (Table 4). FIG. 1 presents a Kaplan-Meierestimate for the distribution of time to hospitalization for any of theliver cirrhosis complications by treatment group for the ITT population.Based on the Kaplan-Meier estimates, the SER 80 mg qhs treatment grouppresented with the highest survival rate of all treatment groups and thecombined IR/SER treatment group had the lowest survival rate; howeverthis effect was not statistically significant (log-rank p=0.2262). FIG.2 presents a Kaplan-Meier estimate for the distribution of time toall-cause mortality by treatment group for the ITT population. Based onthe Kaplan-Meier estimates, the placebo group presented with the highestsurvival rate followed by the SER 80 mg qhs treatment group and thecombined IR/SER treatment group had the lowest survival rate; howeverthis effect was not statistically significant (log-rank p=0.7573). FIG.3 presents a Kaplan-Meier estimate for the distribution of time tohospitalization for any of the liver cirrhosis complications orall-cause mortality by treatment group for the ITT population. Based onthe Kaplan-Meier estimates, the SER 80 mg qhs treatment group presentedwith the highest survival rate and the combined IR/SER treatment grouphad the lowest survival rate; this effect was statistically significant(log-rank p=0.0420).

Supportive Analysis Based on the PP Population

The results on the primary efficacy analysis based on the PP populationwere not consistent with the pairwise comparisons based on the ITTpopulation (Table 4). The primary analysis on the PP populationdemonstrated a statistically significant difference in the time tohospitalization for any of the liver cirrhosis complications orall-cause mortality up to 24 weeks that was in favor of the SER 80 mgqhs treatment group versus placebo (stratified log-rank p=0.0464). Therewere no other statistically significant pairwise comparisons observedbetween the remaining active treatment groups and placebo (Table 5). Theoverall treatment comparison effect for any of the rifaximin SSDtreatments versus placebo was not statistically significant (stratifiedlog-rank p=0.9879). FIG. 4 presents a Kaplan-Meier estimate for thedistribution of time to hospitalization for any of the liver cirrhosiscomplications or all-cause mortality by treatment group for the PPpopulation. Based on the Kaplan-Meier estimates, the SER 80 mg qhstreatment group presented with the highest survival rate and thecombined IR/SER treatment group had the lowest survival rate; thiseffect was statistically significant (log-rank p=0.0182).

TABLE 4 Time to Hospitalization for any of the Liver CirrhosisComplications or All-cause Mortality up to 24 Weeks-ITT Population # of# of Censored Subjects Events <Week 24 Week 24¹ p-value² OverallTreatment Comparison³  Any Rifaximin SSD Treatment 422 50 (11.8%) 31(7.3%) 341 (80.8%) 0.8062  Placebo 94 10 (10.6%) 11 (11.7%) 73 (77.7%)Pairwise Comparisons (versus Placebo)³  Treatment A: Rifaximin SSD 78 7(9.0%) 5 (6.4%) 66 (84.6%) 0.6316  40 mg qhs (IR Tablet)  Treatment B:Rifaximin SSD 91 15 (16.5%) 9 (9.9%) 67 (73.6%) 0.2283  80 mg qhs (IRTablet)  Treatment C: Rifaximin SSD 84 9 (10.7%) 7 (8.3%) 68 (81.0%)0.9666  40 mg qhs (SER Tablet)  Treatment D: Rifaximin SSD 89 4 (4.5%) 6(6.7%) 79 (88.8%) 0.0991  80 mg qhs (SER Tablet)  Treatment E: RifaximinSSD 80 15 (18.8%) 4 (5.0%) 61 (76.3%) 0.1792  80 mg qhs (IR Tablet) andRifaximin  SSD 80 mg qhs (SER Tablet) IR = immediate release; ITT =intent to treat; qhs = once daily at bedtime; SER = sustained extendedrelease; SSD = solid soluble dispersion. ¹Number of subjects censored atWeek 24 (subject did not experience an event and was enrolled in thestudy at Week 24). ²P-value was obtained using a stratified log-ranktest. ³Stratified by analysis region (study centers are grouped within 2regions, centers in the United States and centers in Russia)

TABLE 5 Time to Hospitalization for any of the Liver CirrhosisComplications or All-cause Mortality up to 24 Weeks-PP Population # of #of Censored Subjects Events <Week 24 Week 24² p-value³ Overall TreatmentComparison⁴  Any Rifaximin SSD Treatment 403 46 (11.4%) 31 (7.7%) 326(80.9%) 0.9879  Placebo 90 10 (11.1%) 10 (11.1%) 70 (77.8%) PairwiseComparisons (versus Placebo)⁴  Treatment A: Rifaximin SSD 72 5 (6.9%) 5(6.9%) 62 (86.1%) 0.3116  40 mg qhs (IR Tablet)  Treatment B: RifaximinSSD 88 15 (17.0%) 9 (10.2%) 64 (72.7%) 0.2247  80 mg qhs (IR Tablet) Treatment C: Rifaximin SSD 81 9 (11.1%) 7 (8.6%) 65 (80.2%) 0.9641  40mg qhs (SER Tablet)  Treatment D: Rifaximin SSD 85 3 (3.5%) 6 (7.1%) 76(89.4%) 0.0464  80 mg qhs (SER Tablet)  Treatment E: Rifaximin SSD 77 14(18.2%) 4 (5.2%) 59 (76.6%) 0.2523  80 mg qhs (IR Tablet) and  RifaximinSSD 80 mg qhs  (SER Tablet) IR = immediate release; ITT = intent totreat; PP = per protocol; qhs = once daily at bedtime; SER = sustainedextended release; SSD = solid soluble dispersion. ¹All subjects in theITT population except those that failed inclusion criteria 3, 4 or metexclusion criterion 1. ²Number of subjects censored at Week 24 (subjectdid not experience an event and was enrolled in the study at Week 24.³P-value was obtained using a stratified log-rank test. ⁴Stratified byanalysis region (study centers are grouped within 2 regions, centers inthe United States and centers in Russia).

Prespecified Subgroup Analyses of the Primary Efficacy Endpoint BaselineMELD Category

The influence of a subject's baseline MELD category on the primaryefficacy analysis was evaluated. Baseline MELD subgroups werecategorized as MELD scores of ≤10, 11 to 18, 19 to 24, or ≥25. None ofthe pairwise comparisons versus placebo were statistically significantin any of the subgroups. The overall treatment comparison effect for anyof the rifaximin SSD treatment versus placebo was not statisticallysignificant (MELD score of ≤10: stratified log-rank p=0.8486; MELDscore: 11 to 18 stratified log-rank p=0.7937; MELD score of 19 to 24:stratified log-rank p=0.3154; and MELD score of ≥25: stratified log-rankp=not applicable [1 event out of 1 subject]).

Baseline MELDNa Category

The influence of a subject's baseline MELDNa category on the primaryefficacy analysis was evaluated. Baseline MELDNa subgroups werecategorized as MELDNa scores of ≤10, 11 to 18, 19 to 24, or ≥25. None ofthe pairwise comparisons versus placebo were statistically significantin any of the subgroups. The overall treatment comparison effect for anyof the rifaximin SSD treatment versus placebo was not statisticallysignificant (MELDNa score of ≤10: stratified log-rank p=0.3200; MELDNascore: 11 to 18 stratified log-rank p=0.9368; MELDNa score of 19 to 24:stratified log-rank p=0.2608; and MELDNa score of ≥25: stratifiedlog-rank p=not applicable (3 events out of 4 subjects)).

Baseline Child-Pugh Classification

The influence of a subject's baseline Child-Pugh classification on theprimary efficacy analysis was evaluated. The baseline Child-Pughclassification subgroups were categorized as Class A, Class B, or ClassC. None of the pairwise treatment comparisons versus placebo werestatistically significant in any of the subgroups. The overall treatmentcomparison effect for any of the rifaximin SSD treatments versus placebowas not statistically significant (Class A: stratified log-rank p=notapplicable (zero events); Class B: stratified log-rank p=0.7942 andClass C: stratified log-rank p=0.9516).

Baseline Conn Score

The influence of a subject's baseline Conn score on the primary efficacyanalysis was evaluated. Baseline Conn score subgroups were categorizedas 0, 1, or 2. Table 6 presents the analysis of the primary efficacyendpoint by baseline Conn score. Consistent with the results of the PPpopulation, a statistically significant difference in the time tohospitalization for any of the liver cirrhosis complications orall-cause mortality was observed within the Conn score subgroup 0 andwas in favor of the SER 80 mg qhs treatment group versus placebo(stratified log-rank p=0.0460). This statistical significance was notevident within the Conn score subgroups 1 or 2 (although, subgroup 2 had1 event out of 2 subjects).

The overall treatment comparison effect for any of the rifaximin SSDtreatments versus placebo was not statistically significant for anysubgroup (Conn score 0: stratified log-rank p=0.8915; Conn score 1:stratified log-rank p=0.8251; Conn score 2: not applicable [1 event outof 2 subjects]).

TABLE 6 Analysis of Primary Efficacy Endpoint: Time to Hospitalizationfor any of the Liver Cirrhosis Complications or All-cause Mortality byBaseline Conn Score up to 24 Weeks (Day 170)-ITT Population # of # ofCensored Subjects Events <Week 24 Week 24¹ p-value² Conn Score: 0Overall Treatment Comparison³  Any Rifaximin SSD Treatment 260 34(13.1%) 20 (7.7%) 206 (79.2%) 0.8915  Placebo 57 7 (12.3%) 6 (10.5%) 44(77.2%) Pairwise Comparisons (versus Placebo)³  Treatment A: RifaximinSSD 48 7 (14.6%) 3 (6.3%) 38 (79.2%) 0.7477  40 mg qhs (IR Tablet) Treatment B: Rifaximin SSD 55 11 (20.0%) 7 (12.7%) 37 (67.3%) 0.2297 80 mg qhs (IR Tablet)  Treatment C: Rifaximin SSD 53 4 (7.5%) 5 (9.4%)44 (83.0%) 0.4007  40 mg qhs (SER Tablet)  Treatment D: Rifaximin SSD 481 (2.1%) 4 (8.3%) 43 (89.6%) 0.0460  80 mg qhs (SER Tablet)  TreatmentE: Rifaximin SSD 56 11 (19.6%) 1 (1.8%) 44 (78.6%) 0.3340  80 mg qhs (IRTablet) and  Rifaximin SSD 80 mg qhs  (SER Tablet) Conn Score: 1 OverallTreatment Comparison³  Any Rifaximin SSD Treatment 160 15 (9.4%) 11(6.9%) 134 (83.8%) 0.8251  Placebo 37 3 (8.1%) 5 (13.5%) 29 (78.4%)Pairwise Comparisons (versus Placebo)³  Treatment A: Rifaximin SSD 30 02 (6.7%) 28 (93.3%) 0.0941  40 mg qhs (IR Tablet)  Treatment B:Rifaximin SSD 36 4 (11.1%) 2 (5.6%) 30 (83.3%) 0.7015  80 mg qhs (IRTablet) Pairwise Comparisons (versus Placebo)³  Treatment C: RifaximinSSD 31 5 (16.1%) 2 (6.5%) 24 (77.4%) 0.3467  40 mg qhs (SER Tablet) Treatment D: Rifaximin SSD 39 2 (5.1%) 2 (5.1%) 35 (89.7%) 0.5204  80mg qhs (SER Tablet)  Treatment E: Rifaximin SSD 24 4 (16.7%) 3 (12.5%)17 (70.8%) 0.3075  80 mg qhs (IR Tablet) and  Rifaximin SSD 80 mg qhs (SER Tablet) Conn Score: 2 Overall Treatment Comparison³  Any RifaximinSSD Treatment 2 1 (50.0%) 0 1 (50.0%) Pairwise Comparisons (versusPlacebo)³  Treatment D: Rifaximin SSD 2 1 (50.0%) 0 1 (50.0%)  80 mg qhs(SER Tablet) IR = immediate release; ITT = intent to treat; qhs = oncedaily at bedtime; SER = sustained extended release; SSD = solid solubledispersion. ¹Number of subjects censored at Week 24 (subject did notexperience an event and was enrolled in the study at Week 24). ²P-valuewas obtained using a stratified log-rank test. ³Stratified by analysisregion (study centers are grouped within 2 regions, centers in theUnited States and centers in Russia)

Time Since First Diagnosis of Liver Cirrhosis

The influence of a subject's time since first diagnosis of livercirrhosis on the primary efficacy analysis was evaluated. The time sincefirst diagnosis of liver cirrhosis subgroups were categorized as <947days or ≥947 days. Table 7 presents the analysis of the primary efficacyendpoint by time since first diagnoses of liver cirrhosis. A nearstatistically significant difference in the time to hospitalization forany of the liver cirrhosis complications or all-cause mortality wasobserved within ≥947 days subgroup and, like the PP and baseline Connscore 0 populations, was in favor of the SER 80 mg qhs treatment groupversus placebo (stratified log-rank p=0.0517). The overall treatmentcomparison effect for any of the rifaximin SSD treatment versus placebowas not statistically significant (time since first diagnosis of livercirrhosis: <947 days stratified log-rank p=0.3961; time since firstdiagnosis of liver cirrhosis: ≥947 days stratified log-rank p=0.5689).

TABLE 7 Analysis of Primary Efficacy Endpoint: Time to Hospitalizationfor any of the Liver Cirrhosis Complications or All-cause Mortality byCategorized Time Since First Diagnosis of Liver Cirrhosis up to 24 Weeks(Day 170)-ITT Population # of # of Censored Subjects Events <Week 24Week 24¹ p-value² <947 Days Overall Treatment Comparison³  Any RifaximinSSD Treatment 206 32 (15.5%) 14 (6.8%) 160 (77.7%) 0.3961  Placebo 50 5(10.0%) 7 (14.0%) 38 (76.0%) Pairwise Comparisons (versus Placebo)³ Treatment A: Rifaximin SSD 43 3 (7.0%) 3 (7.0%) 37 (86.0%) 0.4929  40mg qhs (IR Tablet)  Treatment B: Rifaximin SSD 41 8 (19.5%) 7 (17.1%) 26(63.4%) 0.2329  80 mg qhs (IR Tablet)  Treatment C: Rifaximin SSD 46 8(17.4%) 2 (4.3%) 36 (78.3%) 0.3436  40 mg qhs (SER Tablet)  Treatment D:Rifaximin SSD 34 3 (8.8%) 1 (2.9%) 30 (88.2%) 0.7582  80 mg qhs (SERTablet)  Treatment E: Rifaximin SSD 42 10 (23.8%) 1 (2.4%) 31 (73.8%)0.1237  80 mg qhs (IR Tablet) and  Rifaximin SSD 80 mg qhs  (SER Tablet)Censored Censored # of Subjects # of Events # of Subjects # of Events≥947 Days Overall Treatment Comparison³  Any Rifaximin SSD Treatment 21518 (8.4%) 16 (7.4%) 181 (84.2%) 0.5689  Placebo 44 5 (11.4%) 4 (9.1%) 35(79.5%) Pairwise Comparisons (versus Placebo)³  Treatment A: RifaximinSSD 34 4 (11.8%) 1 (2.9%) 29 (85.3%) 0.9598  40 mg qhs (IR Tablet) Treatment B: Rifaximin SSD 50 7 (14.0%) 2 (4.0%) 41 (82.0%) 0.6094  80mg qhs (IR Tablet)  Treatment C: Rifaximin SSD 38 1 (2.6%) 5 (13.2%) 32(84.2%) 0.1523  40 mg qhs (SER Tablet)  Treatment D: Rifaximin SSD 55 1(1.8%) 5 (9.1%) 49 (89.1%) 0.0517  80 mg qhs (SER Tablet)  Treatment E:Rifaximin SSD 38 5 (13.2%) 3 (7.9%) 30 (78.9%) 0.8519  80 mg qhs (IRTablet) and  Rifaximin SSD 80 mg qhs  (SER Tablet) IR = immediaterelease; ITT = intent to treat; qhs = once daily at bedtime; SER =sustained extended release; SSD = solid soluble dispersion. ¹Number ofsubjects censored at Week 24 (subject did not experience an event andwas enrolled in the study at Week 24). ²P-value was obtained using astratified log-rank test. ³Stratified by analysis region (study centersare grouped within 2 regions, centers in the United States and centersin Russia).

Time to Development of Medically Refractory Ascites up to Week 24 (Day170)

Analysis of the time to development of medically refractory ascites upto Week 24 (Day 170) is presented in Table 8.

A statistically significant difference in time to development ofmedically refractory ascites up to 24 Week was observed in favor of theIR 40 mg qhs treatment group versus placebo (stratified log-rankp=0.0308) and in favor of the SER 40 mg qhs treatment group versusplacebo (stratified log-rank p=0.0202). No other pairwise treatmentcomparisons versus placebo were statistically significant. The overalltreatment comparison for any of the rifaximin SSD treatments versusplacebo was not statistically significant.

TABLE 8 Analysis of Secondary Efficacy Endpoint: Time to Development ofMedically Refractory Ascites up to 24 Week (Day170)-ITT Population # of# of Censored Subjects Events <Week 24 Week 24¹ p-value² OverallTreatment Comparison³  Any Rifaximin 422 16 (3.8%) 51 (12.1%) 355(84.1%) 0.0601  SSD Treatment  Placebo 94 0 13 (13.8%) 81 (86.2%)Pairwise Comparisons (versus Placebo)³  Treatment A: 78 4 (5.1%) 8(10.3%) 66 (84.6%) 0.0308  Rifaximin SSD  40 mg qhs  (Immediate Release [IR] Tablet)  Treatment B: 91 3 (3.3%) 18 (19.8%) 70 (76.9%) 0.0721 Rifaximin SSD  80 mg qhs  (Immediate Release  [IR] Tablet)  TreatmentC: 84 5 (6.0%) 9 (10.7%) 70 (83.3%) 0.0202  Rifaximin SSD  40 mg qhs (Sustained Extended  Release [SER] Tablet)  Treatment D: 89 2 (2.2%) 8(9.0%) 79 (88.8%) 0.1508  Rifaximin SSD  80 mg qhs  (Sustained Extended Release [SER] Tablet)  Treatment E: 80 2 (2.5%) 8 (10.0%) 70 (87.5%)0.1319  Rifaximin SSD  80 mg qhs  (IR Tablet) and  Rifaximin SSD  80 mgqhs  (SER Tablet) IR = immediate release; ITT = intent to treat; qhs =once daily at bedtime; SER = sustained extended release; SSD = solidsoluble dispersion. ¹Number of subjects censored at Week 24 (subject didnot experience an event and was enrolled in the study at Week 24).²P-value was obtained using a stratified log-rank test. ³Stratified byanalysis region (study centers are grouped within 2 regions, centers inthe United States and centers in Russia).

Efficacy Conclusions

Based on Kaplan Meier estimates of distribution of time tohospitalization for any of the liver cirrhosis complications orall-cause mortality up to 24 weeks, there was a statisticallysignificant effect in favor of the SER 80 mg qhs and combined IR/SER qhstreatment groups having the highest and lowest survival rates,respectively.

The primary analysis on the PP population did demonstrate astatistically significant difference in the time to hospitalization forany of the liver cirrhosis complications or all-cause mortality up to 24weeks that was in favor of the SER 80 mg qhs treatment group versusplacebo. Kaplan Meier estimates of distribution of time tohospitalization for any of the liver cirrhosis complications orall-cause mortality up to 24 weeks were also statistically significantin favor of the SER 80 mg qhs and combined IR/SER qhs treatment groupshaving the highest and lowest survival rates, respectively.

In the secondary analysis, there was a statistically significantdifference in time to development of medical refractory ascites up toWeek 24 in favor of the IR 40 mg qhs and SER 40 mg qhs treatment groupsversus placebo. There was a statistically significant effect for changefrom baseline in ESS total score was statistically significant treatmentversus placebo effect was observed at Week 4 at the 25th percentile forbaseline (p<0.0001), with the IR 40 mg qhs treatment group presentingwith the greatest decrease from baseline.

These studies show, for the primary analysis, overall time tohospitalization for any of the liver cirrhosis complications orall-cause mortality up to 24 weeks was in favor of the SER 80 mg qhstreatment group versus placebo. In the secondary analysis, statisticallysignificant favorable effects were observed most consistently in the IR40 mg qhs treatment group as well as occurrences in the combined IR/SERqhs and SER 40 mg qhs treatment groups.

The contents of all references (including literature references, issuedpatents, published patent applications, and co-pending patentapplications) cited throughout this application are hereby expresslyincorporated herein in their entireties by reference. Unless otherwisedefined, all technical and scientific terms used herein are accorded themeaning commonly known to one with ordinary skill in the art.

1-35. (canceled)
 36. A method of preventing complications of liverdisease in a subject having liver cirrhosis, comprising administering tothe subject a pharmaceutical composition comprising from about 16 wt %to about 18 wt % rifaximin and from about 16 wt % to about 18 wt %HPMC-AS, wherein the total amount of rifaximin is 40 mg and wherein thecomplications of liver disease are selected from the group consisting ofhepatic encephalopathy (HE), esophageal variceal bleeding (EVB),spontaneous bacterial peritonitis (SBP), and hepatorenal syndrome (HRS).37. The method of claim 36, wherein the composition is an immediaterelease composition.
 38. The method of claim 36, wherein the compositionis in the form of a tablet.
 39. The method of claim 37, wherein thecomposition is in the form of a tablet.
 40. The method of claim 36,wherein the complication of liver disease is hepatic encephalopathy(HE).
 41. The method of claim 36, wherein the complication of liverdisease is esophageal variceal bleeding (EVB)
 42. The method of claim36, wherein the complication of liver disease is spontaneous bacterialperitonitis (SBP).
 43. The method of claim 36, wherein the complicationof liver disease is hepatorenal syndrome (HRS).
 44. The method of claim37, wherein the complication of liver disease is hepatic encephalopathy(HE).
 45. The method of claim 37, wherein the complication of liverdisease is esophageal variceal bleeding (EVB)
 46. The method of claim37, wherein the complication of liver disease is spontaneous bacterialperitonitis (SBP).
 47. The method of claim 37, wherein the complicationof liver disease is hepatorenal syndrome (HRS).